In a world where access to the internet is critical, the sudden and unplanned loss of that access is at minimum disruptive and costly, and at worst catastrophic.
Access to the internet is usually, although not necessarily, made by means of terrestrial connections. The obvious solution to avoid the possibility of loss of access to the internet would be to install a secondary terrestrial connection to the internet which may be used if a primary terrestrial connection to the internet is lost.
Such an arrangement is illustrated schematically in FIG. 1. In this arrangement a client system 100 is connected to an internet service provider 102 which is connected to the internet 104. The internet service provider 102 routes communications between the client system 100 and the internet 104. The client system may, for example, comprise servers 106, 108 connected to a common bus 110. A primary router 112 can route communications between the servers 106, 108 and a primary upstream router 114 in the internet service provider via a primary connection 116. In the event that the primary router 112 and/or the primary connection 116 and/or the primary upstream router 114 fails, communications are routed via a secondary router 118 and a secondary connection 120 to a failover upstream router 115 in the internet service provider 102 which then forwards the communications into the internet.
One problem with this arrangement is that terrestrial connections are likely to be laid in a common conduit, and thus any disruption to the primary connection is also likely to affect the secondary connection. As such, it would be advantageous to provide a secondary connection which is physically diverse from the primary system in order to reduce the possibility that both systems will be lost at the same time, for example, due to a common disruption.
One known way of providing physically diverse primary and secondary connections is to utilize a terrestrial primary connection and a satellite backup system as the secondary connection to the internet. As the terrestrial and satellite connections are physically diverse, there is less likelihood that both the connections will be disrupted at the same time.
Such an arrangement is illustrated schematically in FIG. 2. To show how this arrangement relates to the arrangement illustrated in FIG. 1, like component have been given like reference numbers. As is evident, the primary connection to the internet is substantially the same as that illustrated in FIG. 1. However, the secondary backup connection is implemented by way of a satellite connection. In the event that the primary router 112 and/or the primary upstream router 114 and/or the primary connection 116 fails, communications from the client system 100 are routed via the secondary router 118 to a satellite transceiver 200. The communications are then transmitted via a satellite 202 to a transceiver 204 of a satellite hub 206. The communications can subsequently be forwarded into the internet 104 by a router 208 in the satellite hub over link 209.
A problem with the arrangement illustrated in FIG. 2 is that while internet access may be assured, full internet presence/visibility is not provided. Full internet presence/visibility is desirable to ensure that incoming communications from other internet users are successfully transmitted to the client system. That is, the satellite backup system is not fully transparent to other internet users because it is in a different administrative domain and uses different routing protocols. If the primary route fails, communications from the client system to the internet can readily be re-routed via the backup satellite route. Furthermore, Internet users receiving communications via the backup satellite route may reply via the backup satellite route as the necessary routing information can be provided in the communications sent out from the client system via the satellite route. However, other internet users, which have not received a communication from the client system via the backup satellite route, will not be aware that the primary route has failed and will continue to try and send communications to the client system via the primary route.
Similar problems to those discussed above for connectivity to the internet also exist for connections within an organisation's own private network. In this regard, prior art solutions provide a backup satellite connection for communication between two points in an organisation's own private network rather than providing a backup satellite connection to the internet.
Such an arrangement is illustrated schematically in FIG. 3. To show how this arrangement relates to the arrangements illustrated in FIGS. 1 and 2, like components have been given like reference numbers. In this arrangement the client system 100 is connected to the headquarters 300 of their organisation via primary connection 116 in the organisation's private network. The headquarters 300 is connected to an internet service provider 102 which is connected to the internet 104. The internet service provider 102 routes communications between the headquarters 300 and the internet 104.
The client system may be structured in a similar manner as described in relation to FIG. 2. A primary router 112 can route communications between the servers 106, 108 and a router 302 at headquarters via the primary connection 116. In the event that the primary router 112 and/or the primary connection 116 fail, communications from the client system 100 are routed via the secondary router 118 to a satellite transceiver 200. The communications are then transmitted via a satellite 202 to a transceiver 204 of a satellite hub 206. The communications can subsequently be forwarded to the headquarters by the router 208 in the satellite hub via a connection 304 made between the satellite hub and the headquarters. Similarly, communications from the headquarters can be sent to the client system in the reverse direction via the connection 304 and the satellite system in the event that the primary router 112 and/or the primary connection 116 fail. Routing between the client system 100, the satellite hub 206 and the headquarters 300 is static in nature as the satellite backup connection in this arrangement is only required to provide an alternative route between two fixed points within the organisations private network: the client system 100; and the headquarters 300.
The organisations primary connection to the internet is through headquarters 300 and the internet service provider 102 via connection 303. In the event that connection 303 fails, it may still be possible to re-route signals to the internet via the satellite hub 206 over link 209. However, the arrangement suffers the same problems as outlined above in relation to FIG. 2. Namely, while internet access may be assured, full internet presence/visibility is not provided. That is, the satellite backup system is not fully transparent to other internet users. If the primary route fails, communications from the client system to the internet could be re-routed via the backup satellite route. Furthermore, internet users receiving communications via the backup satellite route may reply via the backup satellite route as the necessary routing information (e.g. as conveyed by network address translation (NAT)) can be provided in the communications sent out from the client system via the satellite route. However, other internet users, which have not received a communication from the client system via the backup satellite route, will not be aware that the primary route has failed and will continue to try and send communications to the client system via the primary route. In addition, providing a satellite backup system within an organisation's private network can be too expensive, especially for SMEs (small and medium sized enterprises) or SOHOs (Small Offices, Home Offices). Further still, backup systems can be difficult to implement in organisations with many sites such as retail chains.
Another known solution to providing backup connectivity requires the use of multiple internet service providers for re-routing communications. However, this solution requires multiple relationships with internet service providers which can be difficult to implement and manage. Furthermore, it may not always be possible to find a second service provider. Additionally, the use of multiple service providers can be expensive and may not offer true physical diversity.